The real ‘Jaws’: Great white shark’s genetic secrets revealed

A great white shark is seen in the waters near Guadalupe Island off the coast of Mexico in this 2012 handout photo obtained by Reuters on February 18, 2019. (Byron Dilkes/Danah Divers/Handout via)

WASHINGTON, February 19 (Reuters): The great white shark, one of the most fearsome predators in the world’s oceans in both fact and fiction, is a formidable creature — right down to its genes.

Scientists on Monday said they have decoded
the genome of Earth’s largest predatory fish, detecting numerous genetic traits
that help explain its remarkable evolutionary success, including molecular
adaptations to enhance wound healing as well as genomic stability such as DNA
repair and DNA damage tolerance.

The great white shark, whose scientific
name is Carcharodon carcharias, boasts a very large genome, 1-1/2 times bigger
than the human genome.

In theory, large genomes with a
lot of repeated DNA, like this shark possesses, and its large body size should
promote a high incidence of genome instability, with much more DNA and many
more cells seemingly vulnerable as targets for damage through an accumulation
of routine mutations.

Just the opposite seems to be the
case for this shark, thanks to adaptations in genes involved in preserving
genome integrity.

“This knowledge, in addition to
providing understanding into how sharks work at their most fundamental level —
their genes — may also be useful in downstream applications to human medicine
to combat cancers and age-related diseases that result from genome
instability,” said Mahmood Shivji, director of the Save Our Seas
Foundation Shark Research Center and Guy Harvey Research Institute at Nova
Southeastern University in Florida.

This species, star of the 1975 Hollywood
blockbuster “Jaws” and its multiple sequels, roams the world’s
oceans, primarily in cool coastal waters.

Sharks are an evolutionary success story,
thriving for more than 400 million years. Our species appeared roughly 300,000
years ago.

The great white shark also displayed
genetic adaptations in several genes that play fundamental roles in wound
healing. For example, a key gene involved in producing a major component of
blood clots was found to have undergone adaptations.

“These adaptations and enrichments of
essential wound-healing genes may underlie the ability of sharks to heal from
wounds so efficiently,” said Cornell University’s Michael Stanhope, co-leader
of the research published in the Proceedings of the National Academy of
Sciences.